A practice which is commonly followed by many dentists when there is a need to prepare a tooth for a crown or to extract a patient's tooth is to suggest to the patient the possibility of replacing the natural tooth with an artificial tooth.
In those instances wherein the natural tooth is to be replaced after extraction by an artificial tooth, or is being prepared for a crown, the dentist commonly preparatory to extracting the tooth or before or after preparation for a crown will attempt to match the coloration of the natural tooth to that of an artificial tooth which will then thereafter be substituted therefor, or will be employed in preparing the crown. This is accomplished conventionally by determining by comparison the particular shade of an artificial tooth that will match the coloration of the natural tooth. Because of the fact that the natural tooth has not yet been extracted, or prepared for a crown, the aforedescribed comparison must be made within the interior of the patient's mouth. One method which is very often used to perform the comparison is to position an artificial tooth having a known coloration adjacent to the natural tooth in the patient's mouth for purposes of comparing the coloration of the artificial tooth with that of the natural teeth. It should be readily apparent that there are a number of factors which will influence the determination of this comparison such as for example, the lighting which is available in the room, the shadows which are cast in the patient's mouth, the extent to which the natural teeth transmit light, etc.
As derived from a reference to the prior art, there have been provided heretofore a variety of different types of devices which are intended to be employed in connection with the performance of a comparison of the coloration of an artificial tooth with that of a natural tooth for which the former is to be substituted. In accordance with the teachings of the prior art, most commonly a set is provided of artificial teeth which differ in coloration one from another. Moreover, each of the artificial teeth in a set is suitably supported on its own individual holder. By way of illustration, reference is had in this regard particularly to U.S. Pat. Nos. 1,207,895; 2,479,543; and 2,805,478. In U.S. Pat. No. 1,207,895, there is shown a set of artificial teeth embodying different colorations which are each supported on an individual mounting. The latter mountings are in turn received in a holder which is generally rectangular in configuration. There is shown in U.S. Pat. No. 2,479,543 a set of artificial teeth wherein the teeth which are each of different coloration are formed integrally with a mounting. A circular holder is provided for purposes of grouping the teeth with a set i.e., for supporting the mountings thereon. U.S. Pat. No. 2,805,478 shows still another embodiment of a tooth shade guide. The latter guide consists of a holder having a generally curved configuration. There is affixed to the holder for pivotal movement relative thereto a multiplicity of radially extending arms. Each of the latter arms at the free end thereof carries an artificial tooth. The artificial teeth which together constitute a set thereof differ one from another insofar as concerns their coloration.
Having determined through the employment of a tooth shade guide such as one of those which has been described in the preceding paragraph the coloration which the artificial tooth should possess, most often the dentist himself will not actually manufacture the artificial tooth. Rather, this is a task which is performed by a dental laboratory. More specifically, the dentist instructs the dental laboratory as to the coloration which the artificial tooth should have in order that it may produce an artificial tooth which will match that of the natural tooth which is being extracted. The manner in which the dentist conveys to the dental laboratory the information regarding the coloration which it is desired that the artificial tooth have is by identifying the coloration by number. Namely, each of the various artificial teeth which are included in a set thereof that forms a tooth shade guide are designated by means of an identifying number. Moreover, both the dentist and the dental laboratory possess the same type of tooth shade guide. Therefore, the dentist need merely tell the dental laboratory the specific type of tooth shade guide which he has utilized for purposes of making the comparison determination and the identifying number of the particular tooth in the set of artificial teeth which together form the tooth shade guide which has been selected as a result of the comparison determination. Thereupon, the dental laboratory need merely refer to that particular artificial tooth in the tooth shade guide which bears the specified identifying number provided thereto by the dentist in order to produce an artificial tooth that embodies the desired coloration.
Down through the years, a number of modifications have been made in the construction of prior art forms of tooth shade guides. By and large these modifications have been directed to attempts to faciliate the manner in which the tooth shade guide is used. Namely, changes have been sought to be made in the configuration of the individual mounting which carries the artificial tooth as well as in the nature of the configuration thereof so as to be able to more easily position the artificial tooth within the patient's mouth in juxtaposed relation to the natural tooth with which the comparison is to be made. The result has been to produce tooth shade guides wherein the mountings are formed of different types of material such as for example, resilient materials or wherein the configuration of the mountings has been modified so as to embody one or more suitably placed bends operable to facilitate the entry of the mounting into the patient's mouth.
Notwithstanding all of the above referenced efforts to effect improvements in the construction of tooth shade guides, one particular difficulty encountered in the employment of a tooth shade guide has had very little attention focused thereon. More specifically, as will be readily apparent from a reference to the prior art, it is only possible to include a limited number of artificial teeth in each tooth shade guide. Consequently, the dentist is limited in the number of different shades of artificial teeth from which he can select in making his comparison determination as to the coloration which the artificial tooth must have in order to match that of the natural tooth for which it is to serve as a replacement. At best therefore, the result is that the coloration selected represents only an approximation of the actual coloration which the artificial tooth should have. In order to achieve a closer approximation to the true color, the dentist in his instructions to the dental laboratory will select the coloration of the artificial tooth in the tooth shade guide which appears to come closest to the shade of the natural tooth and often will request the dental laboratory to provide an artificial tooth which is somewhat darker, more yellow, etc. in shade than the specified artificial tooth. Obviously, this poses a dilemma to the dental laboratory insofar as concerns their determination as to how much darker or how much more yellow, etc. the artificial tooth should be made. The most readily apparent manner of obviating the aforedescribed problem is to increase the number of artificial teeth which are embodied in a tooth shade guide. The difficulty with this proposal however, is that to do so requires providing a holder which is sufficiently large in dimensions so as to be capable of supporting the increased number of artificial teeth. From a practical standpoint, the bulkiness of such a holder as well as the added expense incurred in the manufacture of such a holder and in the manufacture of the added number of artificial teeth have combined to render this proposal undesirable. Of course, it is readily apparent that a holder need not be provided for the mountings which carry the artificial teeth. Namely, a tooth shade guide could be provided which consisted of a multiplicity of artificial teeth which are loose. Such an approach has also proven to be undesirable in that it has been found that the individual mountings are easily lost or misplaced so as not to be readily available when needed. This stems from the fact that each of the artificial teeth including its individual mounting is relatively small in size. Thus, it has been found that a need exists to provide a tooth shade guide which is capable of increasing the number of different shades of artificial teeth from which the dentist is capable of selecting in making his comparison determination as to the coloration of the artificial tooth which most closely corresponds to the coloration of the natural tooth. Moreover, there exists a need to provide such a tooth shade guide which does not suffer from the disadvantages possessed by the tooth shade guides which have been proposed heretofore in an attempt to overcome the problem which dentists have experienced in arriving at an accurate selection of the coloration which the artificial tooth should have.
Accordingly, it is an object of the present invention to provide a novel and improved tooth shade guide operable for use by a dentist in determining by comparison the particular shade of an artificial tooth that may be substituted for a natural tooth of a patient.
It is another object of the present invention to provide such a tooth shade guide which is operable to afford a larger selection of shades of coloration of artificial teeth which can be matched to the coloration of a natural tooth.
A further object of the present invention is to provide such a tooth shade guide wherein the artificial tooth is provided with a covering which is effective to alter the basic color of the artificial tooth to produce a variation in the shade thereof.
A still further object of the present invention is to provide such a tooth shade guide wherein the covering consists of a detachable cap which is mountable with a snap fit on the artificial tooth.
Yet another object of the present invention is to provide such a tooth shade guide which employs artificial teeth and mountings which are presently commercially available as well as, it is expected, those which will become available in the future.
Yet still another object of the present invention is to provide such a tooth shade guide which is easy to employ, yet is relatively inexpensive to manufacture.